This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Data were collected on projects studying the basic properties of T cell receptor (TCR) recognition and the recognition of tumor antigens by TCRs used in the gene therapy of cancer. The aim of the projects included (1) studying the biophysical consequences of antigen modification with the goal of understanding recognition by tumor specific TCRs, (2) studying the structural properties of TCR-peptide/MHC ternary complexes associated with tumor rejection, and (3) studying the structural properties of an unligated TCR to gain insight into conformational properties of binding loops.